Perhaps you're contemplating a question: How many of the genes in your body actually come from the previous generation, or even further back?
In the relationship between grandparents and grandchildren, how many genes does a grandson inherit from his grandfather?
This question leads to deeper reflections: Do you still carry genes from ancestors who lived 2000 years ago?
Today, we'll explore the complex factors behind gene transmission. Perhaps through certain genetic traits, you can connect with your ancestors.
The complexity of gene transmission prevents us from giving a simple answer.
It's generally believed that a grandson inherits about half of his genes from his parents, who each contribute about half from their parents, meaning a grandson gets about one-fourth of his genes from his grandfather.
This conclusion generally holds true because genes are stable.
They accurately replicate themselves during transmission and are passed on to the next generation through germ cells, ensuring genetic stability.
The combination of genes from both parents also promotes a balance in the genetic makeup of the offspring.
Despite this general rule, gene transmission is not a straightforward pairing of genes.
For example, if a grandfather has genes 1 and 2, and a grandmother has genes 3 and 4, the father might inherit genes 1 and 3, while the mother has genes 5 and 6, and the grandson might inherit genes 1 and 5.
Sometimes, gene transmission can be more complex.
For instance, the father's generation might only pass on gene 1 or a combination of genes, so the grandson might not inherit gene 1 at all.
Though the probability of such a scenario is low, it still exists.
It's normal for an individual to have more genes from one parent than the other.
In a reasonable gene transmission process, it's even possible to retain genes from ancestors who lived tens of thousands of years ago.
Scientists have compared the genes of Asians and Europeans with those of Neanderthals and found about 1% to 4% Neanderthal genes.
This suggests that our ancestors had interactions with Neanderthals, leading to the persistence of their genes to this day.
However, tracing genes from hundreds of thousands of years ago is challenging because the randomness of gene transmission poses a risk of gene loss for any particular gene.
Moreover, genes not only possess stability but also variability, which provides opportunities for increased biodiversity.
Various factors can trigger gene mutations, including changes in the external environment or the organism's own needs.
While genetic mutations are advantageous for evolution, they can also lead to congenital diseases.
Despite the uncertainties brought about by gene transmission and mutation, it's precisely this uncertainty that drives human evolution, enabling us to adapt to ever-changing environments.
If we still retain a significant amount of genes from early humans, could we still create such a diverse and colorful human society?
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